Type 8 primaries anyone?

[mmoe]

I've got a quote for some custom type 8 primaries and hope to get a group buy situation put together. These would be completely made from scratch with the proper splines for the factory shafts, upper and lower, and would have the proper upper bearing cavity along with the circlip/retainer ring slots in the upper gear. The holes for drifting in the lower nut will also be present.

I was quoted $600/set for a series of 10 sets, possibly less if there are more. Also, the price could be less if the gearshop has the proper broach for the splines in stock already (he needs me to bring the shafts in to know for sure).

The teeth would be the same as factory, however they would be straight cut rather than helical cut from row to row. I'm still waiting to hear how much more a helical cut (as the factory sprockets are) would cost, but the shop is capable of doing it. At $600/set, we could also have 4 rows of teeth, though I'm not sure that it's necessary nor easy to fit in the case. That would also require modification to the tensioner, so we'll probably be sticking with 3 rows unless there's some outcry about it.

How many would be interested? What further information would you like to have? As it sits right now, 4-6 more sets spoken for would probably be enough to meet the 10 set minimum. If we can get it to 20, we may see the price go down. Given that a used set will usually get this much, even $600 seems pretty reasonable to me.

The gearshop is called Custom Gear, Inc. here in Seattle and was highly recommended to me by The Gear Works (also in Seattle). The work I've seen in the shop appears to be all very high quality. I do a little machine work myself, so I don't say that without a little knowledge about what I'm looking at.

[TooMany2cvs]

Originally Posted by mmoe

I was quoted $600/set for a series of 10 sets, possibly less if there are more.

Rather than remake t8s - which are available, albeit not in huge quantity - would it be possible to make other gearings?

t9s, maybe? (Is there enough space in the primary housing?)
or t8.5s, with the lower sprocket smaller but the same upper and a shorter chain?

[sonett1]

What kind of chains would be used with these sprockets?

[mmoe]

Originally Posted by sonett1

What kind of chains would be used with these sprockets?

The factory original chains would be used, same tooth spacing and same number of links overall.

[sonett1]

Originally Posted by mmoe

The factory original chains would be used, same tooth spacing and same number of links overall.

That could be OK, old chains on new sprockets? It would be good to have new chains.

[euromobile900]

Originally Posted by sonett1

That could be OK, old chains on new sprockets? It would be good to have new chains.

Those're available, at least in North America. For international buyers, mmoe, are you planning on sending chains with the gears? A bulk order from eeuro wouldn't be at all painful.

[mmoe]

Originally Posted by TooMany2cvs

Rather than remake t8s - which are available, albeit not in huge quantity - would it be possible to make other gearings?

t9s, maybe? (Is there enough space in the primary housing?)
or t8.5s, with the lower sprocket smaller but the same upper and a shorter chain?

I didn't answer this earlier because I had to check my suspicions regarding the fit. There are significant design issues with both the upper and lower sprockets that prevent the addition/subtraction of more teeth. The lower sprocket must fit over/around the front input shaft bearing and there is simply not enough meat left to support the teeth at that diameter. The upper sprocket could be made, though it appears that modification to the primary case would be required for clearance (though it would be close). For all practical purposes, type 8 is the limit.

Another option would be a custom ring/pinion which could provide a type 8 revolutions equivalent with type 6 primaries, which would further allow type 9 revs to be produced with type 7 primaries. However, that would require a rebuild to put into service and it may apply more stress than the somewhat undersized gears could handle.

[dmgb5]

Hasn't this been covered before....http://www.saabcentral.com/forums/sh...type+primaries. That said I have type 8's and I might be interested in a second set at the right price.

[mmoe]

Originally Posted by dmgb5

Hasn't this been covered before....http://www.saabcentral.com/forums/sh...type+primaries. That said I have type 8's and I might be interested in a second set at the right price.

The price is listed. The thread you linked to showed a bunch of people saying the same thing, that they'd like a set for the right price but no one ever says what their budget would be. I'd like a set for $100, but that's not reality. $600 is what they will cost (+/- depending on final design), so that information is there. Shipping will be extra of course but they should fit nicely into the flat rate boxes at the USPS, which given the weight will likely be the cheapest method. In the U.S, that would probably be around $20-25 priority and international shipping would be around $45.

In the other thread, no one even found a source that could build them. The gearshop I've found is not only capable, but willing to provide whatever we ask. If we decide we all would prefer the helical cut, it will be a bit more. If we decide we're OK with the straight cut, then this is the estimate given to me. If we wanted a 4th row of teeth, it would be approx. an extra $20/sprocket. The one thing I need to verify is whether or not the gears were spec'd at the 62C rockwell hardness that the originals are. He gave me a specified material, but I don't recall asking what it's native hardness is. I'll also look into what cryo-treating these would cost. IMHO, if the metal is at least 56C, they would probably be fine without treatment, but I will work on getting that spec from the shop.

It should be noted that these are absolutely 100% custom sprockets made from a blank. There would be no use of catalog parts or anything like that. The teeth will be cut to spec, the splines will be cut to spec, the bearing pocket will be cut to spec, the bearing retainer circlip slot will be cut to spec and the clutch shaft retaining ring slot will be cut to spec. All of these specs will match the factory specs for the type 7s, only with more/less teeth where appropriate. The area surrounding the front input shaft bearing will be beefed up as much as possible to provide support to the rear row of teeth, without interfering with the bearing/housing. The holes for the factory input shaft nut drifts will be provided. These will be as close to the factory originals as possible within what I believe to be a reasonable budget.

[euromobile900]

I'd be in if I didn't already have a set! Unfortunately (fortunately?) I just got my grubby hands on some real SAAB ones.

If it means anything to anybody, I've found another part number for the top sprocket bearing, so you won't have to pay through the nose for that either. Same thing as is used in Jeep axles, and sold by SKF:

SAAB # 8710865
Timken #s U298 and U261L (cup and cone respectively) OR U298-90011 (unit part number)
SKF # 331579B
Asking a NAPA auto parts store in the USA for a BR9 (or searching on the Napa site for it) will also get you this bearing, probably an SKF 331579B, and at a rate much cheaper than what eEuroparts or the Saabsite charges. RockAuto also uses the SKF BR9 part number but I haven't actually seen one of those. It comes with a compression sleeve for use in a rear axle, but this is a separate part and means nothing to us (would make a good paperweight). They also go in rear axles of certain American cars (jeep ZJ with 44 or 35 rear axle to name one), as well as in some John Deere implement.

FWIW.